The present invention relates to fiber optic alignment methods and devices and, more particularly, to a fiber optic alignment apparatus for accurately assembling a fiber optic transmitter/receiver to a coupler.
A transmitter/receiver in the form of a gallium arsenide semi-conductor die chip can be mounted to a substrate carrier to provide ease of handling. The semi-conductor chip, however, cannot be mounted to the substrate carrier with sufficient accuracy for aligning the carrier with the optical fibers of a coupler. Commercially available devices are unable to accomplish the task, due to the extremely high tolerances presented by such a small assembly unit. The present invention is for an alignment device and procedure for accomplishing the alignment of the optical fibers of a coupler with the aforementioned die chip and substrate carrier unit.
The alignment device of the current invention aligns and bonds the chip and substrate unit to the coupler. The inventive apparatus has the advantage of allowing the testing of the optical transmission through the fibers during the alignment procedure.
In U.S. Pat. No. 4,553,813, issued on Nov. 19, 1985 to McNaughton et al, for FIBER OPTIC CONNECTOR SYSTEM FOR INTEGRATED CIRCUIT MODULES, a system having an optically terminated module with built-in retention is illustrated. Fiber optic signal lines are connected directly to light emitting diodes mounted upon an integrated circuit chip.
U.S. Pat. No. 4,668,044, issued on May 26, 1987 to D""Auria et al, for OPTOELECTRONIC COUPLER FOR OPTICAL FIBERS PROVIDING ADJUSTABLE LIGHT-ENERGY EXTRACTION AND A BIDIRECTIONAL DATA TRANSMISSION SYSTEM FOR PRACTICAL APPLICATION OF THE COUPLER, comprises a coupler having a photodiode with a central passage, and an end-face that is adjustably distanced from the photodiode in order to adjust the light energy being extracted therefrom.
U.S. Pat. No. 4,883,342, issued to Ishii et al on Nov. 28, 1989 for METHOD OF ASSEMBLING A LIGHT EMITTING DEVICE WITH AN OPTICAL FIBER, includes a light emergence device, an optic fiber connected thereto, and an optical fiber supporting member. The support member is deformable in order to align the optical axes of the light emergence device and the optical fiber.
U.S. Pat. No. 4,650,285, issued on Mar. 17, 1987 to Stevenson, for HOT ALIGNMENT ASSEMBLY METHOD FOR OPTOELECTRONIC PACKAGES, presents a method for assembling semiconductive optoelectronic devices. A hot alignment step comprises applying power to a semiconductor to aid in the optical alignment.
In U.S. Pat. No. 4,623,220, issued to Grabbe et al on Nov. 18, 1986 for LASER TO FIBER CONNECTION, a device for optically coupling a fiber to a solid state laser is illustrated. A fiber is mounted upon a platform in order to align same with a laser. The attachment material has the same thermal properties of the platform material, thereby minimizing thermal expansion or contraction that would misalign the fiber and laser.
In U.S. Pat. No. 4,441,785, issued on Apr. 10, 1984 to Petrozello, for ROTARY FIBER OPTIC SWITCH, a light emitting diode or laser diode is channeled through a group of fibers to engage a fiber optic switch comprising a rotary drum with light channels disposed therein.
In U.S. Pat. No. 4,405,201, issued to Cefarelli et al on Sep. 20, 1983, for FIBER OPTIC CONNECTOR, a connector that couples multiple pairs of fiber optic transmission lines is shown. The fibers are axially aligned within a plug and mating receptacle disposed in an elastomerically supported holder.
In U.S. Pat. No. 5,781,682, an inexpensive package of roughly aligned chips featuring an array of lasers is illustrated. The loose attachment requires no active alignment.
In U.S. Pat. No. 5,655,041, single path optical waveguides are shown. The device does not contain flex circuits or parallel aligned paths.
In U.S. Pat. No. 5,381,494, a coupler device is shown, which comprises pig-tails. There is no teaching to attach this device with a laser chip.
In U.S. Pat. No. 4,790,617, two fiber ends are aligned and joined together. There is no suggestion or teaching of multiple axes alignment.
In U.S. Pat. No. 5,812,258, eccentric sleeves are used to align two optical components. There is no suggestion of multiple axis alignment.
In U.S. Pat. No. 5,671,311, a plurality of ferrules aligned with a pin alignment fixture is shown. The configuration would not be able to accomplish the alignment and testing provided by the current invention.
In accordance with the present invention, there is provided a method and apparatus for precisely coupling a plurality of light receiving members to be aligned with a substrate comprising a plurality of light emitting members. It should be understood that this apparatus can be used not only for coupling to a light transmitter, such as an LED, but also for coupling to a light receiver such as an optical detector. However, for simplicity herein, the light alignment tool is referred to as a transmitter. The substrate contains first and second openings. A coupler to be attached thereto has pins that are to be inserted into the first and second openings, in order to roughly align the light receiving members with the light emitting members of the substrate.
During the coupling process, the connection is tested by actuating the light emitting members and, in conjunction therewith, by analyzing the light intensity of the light received by the receiving members. The light receiving members are adjusted about multiple axes to provide a maximum total intensity of light flux. After the adjustment, a UV curable bonding medium is applied to the coupler and substrate. The bonding medium is then subjected to UV light to cure the bonding medium, thereby permanently joining the parts.
It is an object of this invention to provide an improved method and apparatus for aligning a fiber optic transmitter/receiver to a coupler.
It is another object of the invention to provide an alignment method and apparatus for testing the alignment between a plurality of light emitting and light receiving elements during the multiple axes alignment and bonding procedure to provide maximum intensity of the light flux.